Quiz 92, November 27th, 2020

Welcome to the 92th FOAMed Quiz. 

Enjoy!

Nicole, Joep and Rick

Source image: www.pixabay.com

Question 1

The recently published PLACID-trial is about the use of convalescent plasma in the treatment of admitted patients with COVID-19.

The researchers compared the use of convalescent plasma (2 doses of 200ml convalescent plasma 24 hours apart) plus standard care (intervention group) to standard care alone (control group) in patients with confirmed moderate COVID-19 (PaO2/FiO2 ratio between 200-300 mmHg OR a respiratory rate of >24/min with oxygen saturation 93% or less on room air).

Their primary outcome was progression to serious disease (PaO2/FiO2 ratio <100 mmHg) or death within 28 days.

What did the authors find?

A: Progression to serious disease or death within 28 days was significantly decreased in the intervention group compared to the control group

B: Progression to serious disease or death within 28 days was not significantly different between both groups

C: Progression to serious disease or death within 28 days was significantly increased in the intervention group compared to the control group

The correct answer is B

The PLACID-trial was covered by Simon Carley on St.Emlyn’s this week.

464 adult patients underwent randomization. Convalescent plasma was not associated with a reduction in progression to severe COVID-19 or death (intervention group 19% vs control group 18%). These results are consistent with the previous ConCOVID-trial.

The validity of these results might be affected by large differences in standard of care between hospitals which participated in this study.

Larger ongoing trials, such as the RECOVERY-trial, will help to further address the role of convalescent plasma in patients with COVID-19.

JC: Convalescent plasma in COVID 19 patients.

Source image: www.rebelem.com

Question 2

The subclavian vein is a preferred central venous access site given its fixed puncture location, ease for nursing access and low incidence of infections. However, access can be a bit more challenging compared to the internal jugular vein and there may be a higher chance of complications like arterial puncture and pneumothorax.

This recently published paper is about static ultrasound-guided (needle not directly visualised) puncture versus traditional anatomic landmark guided subclavian vein puncture in the ICU.

What did the authors find?

A: The rate of successful vein puncture was higher in the ultrasound group

B: The rate of pneumothoraces was higher in the ultrasound group

C: The rate of arterial puncture was higher in the ultrasound group

The correct answer is A

RebelEM covered the paper last week on their podcast.

The authors of this study sought to compare the efficacy and safety of static ultrasound-guided puncture with traditional anatomic landmark guided subclavian vein puncture. 95 patients were randomised to the ultrasound group and 98 patients to the landmark group.

The rate of successful vein puncture was higher in the ultrasound group (91 vs 77 percent). The rate of pneumothoraces was higher in the landmark group (0 vs 2 patients) and the rate of arterial puncture was also higher in the landmark group (2 vs 14 percent).

It seems static ultrasound clearly has advantages over the landmark technique. But then again, who doesn’t use ultrasound guidance in central line placement nowadays?

REBEL Cast Ep91: Static Ultrasound vs Landmark Placement of Subclavian Central Lines

Source image: www.LITFL.com

Question 3

This patient has a normal QRS axis. Which of the following leads are most likely reversed?

A: Left arm and left leg

B: Right arm and left leg

C: Left arm and right arm

The correct answer is C

This weeks dr. Smith’s ECG blog is about left ventricular hypertrophy and limb lead misplacement.

Source image: www.LITFL.com

The following happens when right and left are replaced:
– Lead I becomes inverted.
– Leads II and III switch places.
– Leads aVL and aVR switch places.
– Lead aVF remains unchanged.

Source image: www.wikem.org

Question 4

Your patient comes in feeling generally unwell after using amyl nitrite. He is profoundly tachypnoeic and cyanotic, saturation levels reach 88 percent with a non rebreather mask. His blood appears brown. You suspect methemoglobinemia. The pharmacy is already preparing methylene blue.

Which of the following is a contra-indication for methylene blue?

A: COPD exacerbation

B: Sickle cell disease

C: G6PD deficiency

D: Gilbert’s syndrome

The correct answer is C

EMdocs covered methemoglobinemia this week.

Methylene blue is the mainstay of methemoglobinemia treatment. However, by itself methylene blue can cause hemolysis, but the combination of G6PD and methylene blue makes severe hemolysis very likely to occur. Furthermore, it seems methylene blue is not as effective in patients with G6PD deficiency.

EM@3AM: Methemoglobinemia

Source image: www.emottowablog.com

Question 5

Diagnosis of pulmonary embolism (PE) is often challenging. Classic Wells score and D-dimer stretegy probably leads to too many CT-scans. Quite a few risk based diagnostic strategies for diagnosis of PE have been suggested and validated so far, leading to less scanning with acceptable sensitivity.

Which of the following diagnostic strategies lead to the lowest imaging rate while maintaining high sensitivity for PE according to available evidence?

A: Classic Wells score strategy

B: YEARS algorithm strategy (link)

C: Adjusted d-dimer based on Wells score (threshold of 1000 vs 500 vs direct CT, the 2019 PEGed paper) strategy

D: Age adjusted d-dimer strategy (link)

The correct answer is C

EMOttawa covered diagnostic strategies in suspected pulmonary embolism.

In the 2019 PEGeD paper, about 2000 patients with suspected PE were divided into three groups based on the Wells score. Patients were deemed low risk (d-dimer cutoff 1000) if the Wells score was 4 or lower, moderate risk (d-dimer cutoff 500) if the Wells score was higher than 4 and lower than 6,5, or high risk (direct imaging) if the Wells score was 6,5 or higher. The vast majority of patients were low risk and no venous thrombo-embolisms were missed.

The standard Wells strategy leads to a 51.9% imaging rate, the Age-adjusted strategy to 42.9%, the YEARS strategy to 36.3% and the PEDeg strategy to 34.3%.

The D-Dimer Dilemma: It’s Use In Low-Risk PE

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This quiz was written by Nicole van Groningen and Joep Hermans

Reviewed and edited by Rick Thissen